Many non-driving-related vehicle systems, such as navigation systems, do not allow a driver to input information when the vehicle is moving or in gear. These controls tend to be over inclusive because they prevent all user input, or they prevent user input in all cases, even though the degree of attention and manual interaction required of the driver may vary widely depending on the circumstances and driving conditions. For example, some interactions by a driver may be of a limited nature, such as turning off the radio with a single button push, and thus involve minimal engagement, while other types of interactions may be more substantial, such as entering an address from scratch on a navigation system, and thus involve more significant driver engagement. In addition, some driving environments, such as those involving a winding road, traffic, or inclement weather, demand more driver attentiveness than other driving environments, such as driving on a straight road at a reasonable rate of speed on a clear day. Existing restrictions on a driver's interactions with vehicle functions do not reflect the driver attention requirements associated with the variety of environments in which a driver may be operating a vehicle. Moreover, the restrictions currently employed may be viewed as onerous by drivers, which could make drivers less likely to pay attention to and/or adhere to controls imposed by the vehicle interface systems.
In addition, if a driver suddenly encounters challenging driving conditions such as traffic or inclement weather, the driver may desire to activate functions that relate to the relevant driving environment. Because vehicles often are equipped with a single display that is needed for several vehicle functions (such as a multimedia system, a navigation system, and a climate control system), it is incumbent upon the driver to affirmatively switch the display's functionality to the functionality that is most applicable to the driver's current situation, such as rerouting functionalities on the navigation system or changing the channel to a weather-related station on the multimedia system. This generally requires a visual-manual interaction, which may entail significant driver engagement and attention. On the other hand, the systems described above that restrict the driver from interacting with these functionalities, if employed, may prevent the driver from obtaining critical information that relates to the driving environment.